When gangue is applied to cementitious materials as fine aggregate,the defects of coal gangue fine aggregate(CFA),such as large porosity,high water absorption,and high surface tension,lead to poor mechanical propertie...When gangue is applied to cementitious materials as fine aggregate,the defects of coal gangue fine aggregate(CFA),such as large porosity,high water absorption,and high surface tension,lead to poor mechanical properties of cementitious materials,which limits its large-scale application in the construction field.In this paper,CFA was strengthened using water glass strengthening,microbial-induced mineralization strengthening,and composite strengthening methods,and the effects of the three strengthening methods on the basic properties of CFA,the mechanical properties of mortar,and the interfacial transition zone(ITZ)were explored.The strengthening mechanism was investigated via X-ray diffraction(XRD),scanning electron microscope(SEM),nanoindentation,and other testing methods.The three strengthening methods were evaluated based on the basic principles of life cycle assessment(LCA).Microbial-induced mineralization can utilize the biological activity of bacteria to achieve targeted repair of the tiny pores of aggregates.Water glass strengthening fills CFA pores and coats the CFA surface with a substance such as a gel produced by the water glass.A composite strengthening treatment can utilize the synergistic reinforcement effect of two single treatments to improve the basic properties of the aggregate.The apparent density of the reinforced CFA increased by 7.69%,the water absorption decreased by 13.07%,and the crushing index decreased by 73.67%.The 3 d compressive strength of the cement mortar prepared with CFA reinforced with composites increased by 44.58%,the 28 d compressive strength increased by 15.43%,and the width of the mortar ITZ decreased from 60 to 30µm.Water glass strengthening has a smaller environmental impact than microbial strengthening does composite strengthening,and composite strengthening produces an environmental impact that is the sum of the two single strengthening methods.展开更多
基金funded by the First-class Subject Cultivation Project of Henan Polytechnic University(No.AQ20250705)the Natural Science Foundation of Henan Province of China(No.242300420023)+1 种基金the Fundamental Research Funds for the Universities of Henan Province(Nos.NSFRF240802,NSFRF230603)Henan Outstanding Foreign Scientists’Workroom(No.GZS2021003).
文摘When gangue is applied to cementitious materials as fine aggregate,the defects of coal gangue fine aggregate(CFA),such as large porosity,high water absorption,and high surface tension,lead to poor mechanical properties of cementitious materials,which limits its large-scale application in the construction field.In this paper,CFA was strengthened using water glass strengthening,microbial-induced mineralization strengthening,and composite strengthening methods,and the effects of the three strengthening methods on the basic properties of CFA,the mechanical properties of mortar,and the interfacial transition zone(ITZ)were explored.The strengthening mechanism was investigated via X-ray diffraction(XRD),scanning electron microscope(SEM),nanoindentation,and other testing methods.The three strengthening methods were evaluated based on the basic principles of life cycle assessment(LCA).Microbial-induced mineralization can utilize the biological activity of bacteria to achieve targeted repair of the tiny pores of aggregates.Water glass strengthening fills CFA pores and coats the CFA surface with a substance such as a gel produced by the water glass.A composite strengthening treatment can utilize the synergistic reinforcement effect of two single treatments to improve the basic properties of the aggregate.The apparent density of the reinforced CFA increased by 7.69%,the water absorption decreased by 13.07%,and the crushing index decreased by 73.67%.The 3 d compressive strength of the cement mortar prepared with CFA reinforced with composites increased by 44.58%,the 28 d compressive strength increased by 15.43%,and the width of the mortar ITZ decreased from 60 to 30µm.Water glass strengthening has a smaller environmental impact than microbial strengthening does composite strengthening,and composite strengthening produces an environmental impact that is the sum of the two single strengthening methods.
